Core A, Microscopy, comprises valuable, electron and modern light microscopic tools that are made available as routine services to Program Project members. The services provided have been crucial for individual laboratory projects, and intra-programmatic research. Core A was established in the original application to meet the growing needs of the investigators in this area and has expanded in this renewal to include Dr. Farquhar as the core leader bringing her expertise as a microscopist due to the recent retirement of Dr. Feramisco. Electron microscopy facilities under her direction are located in the Center for Molecular Medicine and contain state of the art microscopes and specialized preparatory equipment. The core also includes Dr. Patel as a co-investigator who has expertise in light microscopy and has worked over ten years with Dr. Feramisco and the newly established School of Medicine (SOM) Microscopy Core which includes 2- photon confocal, spinning disk, super-resolution (purchase planned) and deconvolution systems. We propose in this application to fund two part-time research assistants to provide dedicated support to PPG members by 1) providing standardized training in the use of electron microscopy and 3-D fluorescence microscopes, 2) training individuals within this PPG to take full advantage of the enhanced scientific visualization software available in our group, and 3) providing hands-on help with the use of the many microscopes available. With increasing frequency, current PPG investigators are making use of these enhanced features, and the proposed Core A will facilitate the ability of PPG members to access these services in a timely and cost-efficient manner.